Filtration medium comprising a carbon oxychalcogenide

ABSTRACT

Described herein is a filtration medium comprising a carbon substrate having a surface of CO x E y , wherein E is selected from at least one of S, Se, and Te; and wherein x is no more than 0.1 and y is 0.005 to 0.3; a filtration device comprising the filtration medium; and methods of removing chloramines from aqueous solutions.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage filing under 35 U.S.C. 371 ofPCT/US2012/052502, filed Aug. 27, 2012, which claims priority to U.S.Application No. 61/533297, filed Sep. 12, 2011, the disclosure of whichis incorporated by reference in its/their entirety herein.

TECHNICAL FIELD

A composition having a surface comprising a carbon oxychalcogenide isdescribed, which is used as a filtration medium, along with methods ofmaking and use.

BACKGROUND

Chloramine is commonly used in low concentration as a secondarydisinfectant in municipal water distribution systems as an alternativeto chlorination with free chlorine. Concerns over taste and odor ofchloramine treated water have led to an increase in the demand for waterfilters with chloramine removal capabilities.

Carbon particles, such as activated carbon particles, have been used toremove chloramine from aqueous streams. Improvements in removal ofchloramine can be achieved by reducing the mean particle diameter of thecarbon and by increasing the carbon bed contact time. Althoughparameters such as contact time and mean particle diameter are known toaffect chloramine removal efficiencies, removal performance is neitherwell understood nor particularly effective.

U.S. Pat. No. 5,338,458 (Carrubba et al.) discloses an improved processfor the removal of chloramine from gas or liquid media by contacting themedia with a catalytically-active carbonaceous char.

U.S. Pat. No. 6,699,393 (Baker et al.) shows improved chloramine removalfrom fluid streams, when the fluid stream is contacted with an activatedcarbon, which has been pyrolyzed in the presence of nitrogen-containingmolecules, versus a catalytically-active carbonaceous char.

SUMMARY

There is a desire to provide a filtration medium, which is lessexpensive and/or more efficient at the removal of chloramine thancurrently available filtration media. In some instances, there is also adesire to provide a carbon-based system, which is in the form of a solidblock activated carbon to remove chloramine. In other instances, thereis a desire to have a granular material that may be used in a packedbed. In still other instances, there is a desire to provide a materialthat may be used in a web-form.

In one aspect, a filtration device is provided comprising a fluidconduit fluidly connecting a fluid inlet to a fluid outlet; and a filtermedium disposed in the fluid conduit; the filter medium comprising acarbon substrate having a surface of CO_(x)E_(y), wherein E is selectedfrom at least one of S, Se, and Te; and wherein x is no more than 0.1,and y is 0.005 to 0.3.

In another aspect, a water filtration device is provided comprising aliquid conduit fluidly connecting a liquid inlet to a liquid outlet; anda filter medium disposed in the fluid conduit; the filter mediumcomprising a carbon substrate having a surface of CO_(x)E_(y), wherein Eis selected from at least one of S, Se, and Te; and wherein x is no morethan 0.1, and y is 0.005 to 0.3.

In yet another aspect, a method from removing chloramine from aqueoussolutions is provided comprising: providing an aqueous solutioncomprising chloramine and contacting the aqueous solution with acomposition comprising a carbon substrate having a surface ofCO_(x)E_(y), wherein E is selected from at least one of S, Se, and Te;and wherein x is no more than 0.1, and y is 0.005 to 0.3.

In still another aspect, a method of making a carbon oxychalcogenide isprovided comprising: contacting a carbon substrate with achalcogen-containing compound; and heating to a temperature between 300to 1200° C. in the presence of oxygen, wherein the form of oxygen isselected from the group consisting of: an inert diluent gas, water,steam, or combinations thereof.

In yet another aspect, a method of making a carbon oxychalcogenide isprovided comprising: contacting a carbon substrate with an oxidizingagent to form an oxidized carbon substrate; providing achalcogen-containing compound; and contacting the oxidized carbonsubstrate and the chalcogen-containing compound and heating to atemperature between 300 to 1200° C.

In another aspect, a composition is provided comprising a carbonsubstrate having a surface comprising CO_(x)E_(y), wherein C, O, and Echemically interact; wherein E is selected from at least one of S, Se,and Te; and wherein x is 0.01 to 0.1, and y is 0.005 to 0.3.

The above summary is not intended to describe each embodiment. Thedetails of one or more embodiments of the invention are also set forthin the description below. Other features, objects, and advantages willbe apparent from the description and from the claims.

DESCRIPTION OF THE FIGURES

FIG. 1 is a chart of the percent chloramine reduction versus time forComparative Example B, Examples 6-7 and Examples 26-27.

FIG. 2 is a chart of the percent chloramine reduction versus time forComparative Examples A-B, and Examples 28A-D.

FIG. 3 is a chart of the percent chloramine reduction versus time forComparative Example B, and Examples 28C, 29, and 30.

FIG. 4 is a chart of the percent chloramine reduction versus time forComparative Example B, and Examples 29C and 31.

FIG. 5 is a chart of the concentration of chloramines in the effluentversus the throughput for Examples 35 and 36 and Carbon Substrates M andN.

DETAILED DESCRIPTION

As used herein, the term

“a”, “an”, and “the” are used interchangeably and mean one or more; and

“and/or” is used to indicate one or both stated cases may occur, forexample A and/or B includes, (A and B) and (A or B).

Also herein, recitation of ranges by endpoints includes all numberssubsumed within that range (e.g., 1 to 10 includes 1.4, 1.9, 2.33, 5.75,9.98, etc.).

Also herein, recitation of “at least one” includes all numbers of oneand greater (e.g., at least 2, at least 4, at least 6, at least 8, atleast 10, at least 25, at least 50, at least 100, etc.).

The present disclosure is directed to a carbon substrate comprising asurface of a carbon oxychalcogenide. It has been found that suchcompositions may be useful for the removal of chloramine from aqueoussolutions.

Carbon has several allotropes, including diamond, graphite, andamorphous carbon. In one embodiment, the carbon substrate comprises asubstantial amount of sp² hybridized carbon. In other words, the carbonsubstrate has no more than 20%, 15%, 12% or even 10% sp³ hybridizedcarbon. As the sp³ hybridized carbon content increases, the sp²hybridized carbon substrate progressively changes into a dense,isotropic network of tetrahedral carbon.

The morphology of the carbon substrate is not particularly limited andmay include a non-particulate, a particulate, or an aggregate. Exemplarymorphologies include: a carbon block, a carbon monolith, foams, films,fibers, nanotubes, and nano-onions. A non-particulate is a substratethat is not composed of discernable, distinct particles. A particulatesubstrate is a substrate that has discernable particles, wherein theparticle may be spherical or irregular in shape and has an averagediameter of at least 0.1, 1, 5, 10, 20, or even 40 micrometers (μm) toat most 75 μm, 100 μm, 500 μm, 1 millimeter (mm), 2 mm, 4 mm, 6.5 mm, oreven 7 mm. An aggregate (or a composite) is formed by the joining orconglomeration of smaller particles with one another or with largercarrier particles or surfaces. The aggregates may be free standing(self-supporting against gravity).

Typically, the morphology the carbon substrate will be selected based onthe application. For example, particulate with a large particle size isdesirable when the compositions of the present disclosure are used inapplications requiring low pressure drops such as in beds through whichgases or liquids are passed. Granular activated carbon available underthe trade designation “RGC” by Mead Westvaco Corp, Richmond, Va. may bepreferred in water treatment; while activated coconut carbon (20×25mesh) available under the trade designation “KURARAY GG” by KurarayChemical Co., LTD, Okayama, Japan may be preferable for air purificationapplications on account of the lower pressure drop associated with itslarger particle size; and a very fine particle sized carbon blackavailable under the trade designation “BLACK PEARLS 2000” by Cabot Corp.Alpharetta, Ga. may be preferable for electrocatalysis on account of itshigher electrical conductivity.

The size of the pores of the carbon substrate can be selected based onthe application. The carbon substrate may be microporous carbon,macroporous carbon, mesoporous carbon, or a mixture thereof.

Particularly useful are carbon substrates that are substantiallydisordered and have high surface areas (e.g., at least 100, 500, 600 oreven 700 m²/g; and at most 1000, 1200, 1400, 1500, or even 1800 m²/gbased on BET (Brunauer Emmet Teller method) nitrogen adsorption). Asused herein, substantially disordered means that the carbon substratehas in-plane domain sizes of about 10-50 Å (Angstrom).

In one embodiment, the carbon substrate is comprised of activatedcarbon, in other words carbon that has been processed to make it highlyporous (i.e., having a large number of pores per unit volume), whichthus, imparts a high surface area.

In the present disclosure, the surface of the carbon substrate comprisesCO_(x)E_(y), wherein E is sulfur, selenium, tellurium, or combinationsthereof; wherein x is no more than 0.1 and y is 0.005 to 0.3. In oneembodiment, x is 0 or is at least 0.005, 0.01, 0.02, 0.03, 0.04, or even0.05; and is at most 0.07, 0.08, 0.09, 0.1, 0.12, 0.15, or even 0.2. Inone embodiment, y is at least 0.001, 0.005, 0.01, 0.02, 0.03, 0.04,0.05, or even 0.06; and at most 0.12, 0.14, 0.15, 0.16, 0.18, 0.2, 0.22,0.25, 0.3, 0.35, or even 0.4.

In one embodiment, the carbon substrate has a surface consistingessentially of CO_(x)E_(y), meaning that the surface necessarilyincludes carbon, oxygen, and E and may also include other atoms so longas the other atoms do not materially affect the basic and novelproperties of the invention. In other words, besides carbon, oxygen, andthe chalcogen, the surface of the substrate comprises less than 10% oreven less than 5% total of other atoms. These other atoms may originatein the starting materials. For example, a carbon substrate, prior toreactions as described in this disclosure, may contain potassium orminor amounts of other elements, which are not removed duringmanufacturing and thus, are present in the final product.

If sulfur is used as the chalcogenide, the sulfur may be present inamounts greater than 1.2, 1.3, 1.5, 1.8, 2.0, 4.0, 6.0, 8.0 or even 10.0mass % sulfur based on the total mass of the carbon substrate.

In one embodiment, the compositions of the present disclosure compriseless than 0.90, 0.80, 0.70, 0.50, 0.30, 0.10, 0.05, 0.01, or even 0.005mass % nitrogen based on the total mass of the carbon substrate.

In one embodiment, the compositions of the present disclosure aresubstantially free of hydrogen, comprising less than 0.40, 0.30, 0.20,0.10, 0.05, or even 0.01 mass % hydrogen based on the total mass of thecarbon substrate.

The compositions of the present disclosure are made by exposing a carbonsubstrate to a chalogen or chalogen-containing compound, and optionallyoxygen. The chalcogen, as used herein to refer to sulfur, selenium,tellurium, is reacted onto the carbon substrate, by exposing a solid,liquid, or gas form of the chalogen or chalcogen-containing compound tothe carbon substrate under heating conditions.

Useful sulfur-containing compounds include, but are not limited toelemental sulfur, SO₂, SOCl₂, SO₂Cl₂, CS₂, COS, H₂S, and ethylenesulfide.

Useful selenium compounds include but are not limited to elementalselenium, SeO₂ and SeS₂.

Useful tellurium compounds include but are not limited to elementaltellurium, TeO₂ and (HO)₆Te.

In one embodiment, the sulfur, selenium, and tellurium compounds may beused in combination with one another to generate a carbonoxychalcogenide containing more than one chalcogenide element, forexample, sulfur and selenium.

In addition to a chalcogen, the surface of the carbon substrate alsocomprises oxygen. The carbon substrate, as received, may containchemically significant amounts of oxygen attached to surface carbonatoms. For example, according to X-ray photoelectron spectroscopic (XPS)analysis, RGC contains about 2.9 atomic percent of oxygen. This amountof oxygen may be sufficient for the present disclosure but, when higheramounts of surface oxygen are desired, additional oxygen may beincorporated into the carbon.

In one embodiment, additional oxygen may be added to the carbonsubstrate before exposure to the chalcogen-containing compound. Forexample, the carbon substrate can be heated in air or treated withaqueous nitric acid, ammonium persulfate, ozone, hydrogen peroxide,potassium permanganate, Fenton's Reagent, or other well known oxidizingagents.

In another embodiment, additional oxygen can be incorporated into thecompositions of the present disclosure by carrying out the reactionbetween the carbon substrate and the chalcogen-containing compound inthe presence of air or water. The amount of air used must be limited toprevent combustion of the carbon. Additional oxygen may also be suppliedby addition of water or steam, which can be added during the heatingreaction or may be present on the surface of the carbon substrates, suchas in the case of high surface area carbonaceous materials, particularlyhydrophilic oxidized carbons, which chemisorb water. Oxygen may be addedduring the heating reaction in the form of dioxygen, sulfur dioxide,carbon dioxide, or combinations thereof.

In addition to adding an oxygen source during heating of the carbon andthe chalcogen, in an alternative embodiment, the heating is conducted inthe absence of added oxygen.

Reactions of elemental carbon typically exhibit large activationenergies and so are conducted at high temperature. Reactions used tointroduce chalcogens and optionally oxygen into the carbon substratesurface may be conducted at a temperature of at least 200, 250, 300,400, or even 500° C.; and at most 650, 700, 800, 900, 1000, 1200, oreven 1400° C. As will be shown in the examples, in one embodiment, asthe reaction temperature increases the composition of the presentdisclosure becomes more efficient at the removal of chloramine.

The thermal reaction may occur in air. However, to control combustion,it is possible to carry out the thermal reaction under vacuum; with apurge, such as a nitrogen purge; or in an inert atmosphere where the airis pulled from the reaction vessel using a vacuum and then dry nitrogenis used to back-fill the reaction vessel.

The chalcogen-containing compound may be used in the solid, liquid orgas form. Reaction temperatures, which are above the boiling point ofthe chalcogen-containing compounds are used, resulting in solid-gasreaction chemistry.

In one embodiment, the carbon substrate is wetted with a liquidchalcogen-containing compound and then exposed to the reactiontemperature and optional oxygen to form the carbon oxychalcogenidesurface. These reactions occur at the surface of the carbon substrate.In the case of a porous carbon substrate, the carbon oxychalcogenide maycoat (or cover) the surface of the pores of the porous carbon substrate.

The compositions of the present disclosure are obtained via solid-gas(or solid-vapor) chemistry. In reactions of this class, only the outerportions of the carbon substrate are exposed to the reactive gas. Suchreactions can become self-limiting in that an overlayer of productinhibits inward diffusion of the gas. In such a case, the new compoundsthat form are confined to regions near the surface and comprise asurface compound. Generally, this means that reactions occur at depthsof 10 nanometers (nm) or less on the carbon substrate to form theCO_(x)E_(y) coating.

When the carbon substrate is a large particle, a core-shell structureresults, where the core is the carbon substrate, which is covered by ashell or second layer comprising the carbon oxychalcogenide.

Because the reaction disclosed herein is a surface reaction, when thecarbon material is in the form of small particles with high surface area(e.g., RGC powder nominally −325 mesh, having a nominal surface area of1400-1800 m²/g), then the surface and interior of the particle maybecome coextensive. In one instance there may be no apparent chemicaldistinction between the outer surface and the interior of the particle.In another instance, the chalcogen content on the bulk can approach oreven exceed that on the surface.

The solid-vapor process of this disclosure permits penetration of smallmolecule reactants into micropores and niches formed by highly irregularsurfaces. This results in an advantageous, even distribution ofchalcogen.

Because not all of the chalcogenide from the chalcogen-containingcompound is incorporated into the carbon substrate surface (e.g., somemay be converted to COE or H₂E), it is important to analyze theresulting composition to determine the atom fraction of carbon, oxygen,and chalcogen on the carbon substrate surface.

In the present disclosure, the atom fraction of carbon (C), oxygen (O),and chalcogen (E) on the carbon substrate surface is shown asCO_(x)E_(y), where in one embodiment, x is 0 or is at least 0.005, 0.01,0.02, 0.03, 0.04, or even 0.05; and at most 0.07, 0.08, 0.09, 0.1, 0.12,0.15, or even 0.2; and y is at least 0.001, 0.005, 0.01, 0.02, 0.03,0.04, 0.05, or even 0.06; and is at most 0.12, 0.14, 0.15, 0.16, 0.18,0.2, 0.22, 0.25, 0.3, 0.35, or even 0.4.

In one embodiment of the present disclosure, the carbon, oxygen, andchalcogen of the disclosed composition chemically interact with oneanother, meaning, that these elements may be combined chemically (i.e.,covalent chemical bonding between contiguous elements) or there may beweaker interactions between non-contiguous elements, such as hydrogenbonding.

Based on the analysis of compositions of the present disclosure, in atleast one embodiment, the oxygen and chalcogen are combined chemicallyon the surface of the carbon substrate. The oxygen and carbon are anintegral part of the surface of the carbon substrate and are not easilyremoved by heating to 400° C. The nature of the structure and bonding ofthe carbon oxychalcogenides is complex. Carefully deconvoluted XPS(X-ray photoelectron spectroscopy) spectra of the resulting compositionsof the present disclosure reveal that sulfur is in four differentchemical environments with S2p_(3/2) binding energies of about 162.0,164.3, 165.8 and 168.9 eV [C(1s)≡285.0 eV]. They therefore containchemically combined sulfur in three formal valence states [S(VI), S(IV)and S(II)] and four different chemical environments. These chemicalenvironments are: (1) S(VI) as in SO₄ ²⁻ or organic sulfones, C—SO₂—C(2)S(IV) as in organic sulfoxides, C—SO—C, (3) S(II) as in thiophene and(4) S(II) as in organic sulfides, C—S—C or disulfides, C—S—S—C.

In one embodiment, the compositions of the present disclosure have highthermal stability. For example, with carbon oxysulfides, significantweight loss under nitrogen does not begin until about 200° C., wellabove the boiling point of sulfur, indicating that the compositions ofthe present disclosure are not mere physical mixtures of startingmaterials.

By using a solid-vapor process to incorporate the carbon oxychalcogenidesurface onto the carbon substrate, several advantages may be realized.Because the reaction may be solventless or at least free of organicsolvent, no drying operation is needed to isolate the product. Further,there are generally no non-volatile by-products that remain to clogsmall pores in the solid. If no solvent is used, the process asdescribed herein can be envisioned to run as a continuous process, whichcan reduce cost and/or increase throughput.

In one embodiment, the composition of the present disclosure may be usedto remove chloramines.

In one embodiment, the composition of the present disclosure may be usedto remove chloramines from a fluid stream, particularly an aqueous fluidstream. Chloramines are formed from the aqueous reaction between ammoniaand chlorine (hypochlorite). Thus, adding ammonia (NH₃) to achlorination system converts chlorine to chloramines Specifically,monochloramine, hereafter referred to as “chloramine,” in lowconcentrations arise from the disinfection of potable water sources.

Although not wanting to be bound by theory, it is believed that thecarbon, chalcogen, oxygen atoms on the surface of the carbon substrateform particular chemical moieties, such that the chalcogen is present inone or more forms that can be oxidized by chloramines. This results inthe destruction and removal of chloramines.

In one embodiment, the composition of the present disclosure may be usedas a filtration medium. Because of the ability of the compositions ofthe present disclosure to remove chloramine, the compositions of thepresent disclosure may be used as a filtration media. Filtration methodsas known in the art can be used.

The carbon substrates comprising a surface of carbon oxychalcogenidesmay be used either alone, or mixed with inert diluents or functionallyactive materials such as adsorbents. For example the oxysulfide preparedfrom RGC carbon may be mixed intimately or layered in beds with carbonthat has higher capacity for adsorption of volatile organic compounds.In this way, an adsorbent system with more than one functionality can beproduced.

The composition of the present disclosure may be used in a powderedform, a granular form, or shaped into a desired form. For example, thecomposition of the present disclosure may be a compressed blend of thecarbon substrates comprising the carbon oxychalcogen and a bindermaterial, such as a polyethylene, e.g., an ultra high molecular weightPE, or a high-density polyethylene (HDPE). In another embodiment, thecomposition of the present disclosure may be loaded into web, such as ablown microfiber, which may or may not be compacted such as described inU.S. Publ. No. 2009/0039028 (Eaton et al.) herein incorporated in itsentirety.

In one embodiment, the carbon substrate comprising the carbonoxychalcogenide may be disposed in a fluid conduit, wherein the fluidconduit has a fluid inlet and a fluid outlet, with the filtration media(e.g., carbon substrate comprising the carbon oxychalcogenide) disposedtherebetween. A chloramine-containing solution may then be passed fromthe fluid inlet into the fluid conduit to contact the filtration media.The filtrate (solution passing out of the fluid out) should contain lessthan 1, 0.5, 0.1, or even less than 0.05 ppm (parts per million)chloramines.

Embodiments of the present disclosure include:

Item 1. A filtration device comprising a fluid conduit fluidlyconnecting a fluid inlet to a fluid outlet; and a filter medium disposedin the fluid conduit; the filter medium comprising a carbon substratehaving a surface of CO_(x)E_(y), wherein E is selected from at least oneof S, Se, and Te; and wherein x is no more than 0.1, and y is 0.005 to0.3.

Item 2. The filtration device of item 1, wherein x is 0.01 to 0.1.

Item 3. The filtration device of any one of the previous items, whereinE is sulfur and the sulfur is chemically combined with carbon.

Item 4. The filtration device of any one of the previous items, whereinthe filter medium comprises the carbon substrate having a surface ofCO_(x)E_(y) and a binder.

Item 5. The filtration device of any one of items 1-3, wherein thefilter medium comprises the carbon substrate having a surface ofCO_(x)E_(y) and a web.

Item 6. A water filtration device comprising a liquid conduit fluidlyconnecting a liquid inlet to a liquid outlet; and a filter mediumdisposed in the fluid conduit; the filter medium comprising a carbonsubstrate having a surface of CO_(x)E_(y), wherein E is selected from atleast one of S, Se, and Te; and wherein x is no more than 1, and y is0.005 to 0.3.

Item 7. The water filtration device of item 1, wherein x is 0.01 to 0.1.

Item 8. The water filtration device of any one of items 6-7, wherein Eis sulfur and the sulfur is chemically combined with carbon.

Item 9. The water filtration device of items 6-8, wherein the filtermedium comprises the carbon substrate having a surface of CO_(x)E_(y)and a binder.

Item 10. The water filtration device of any one of items 6-8, whereinthe filter medium comprises the carbon substrate having a surface ofCO_(x)E_(y) and a web.

Item 11. A method for removing chloramine from aqueous solutionscomprising: providing an aqueous solution comprising chloramine andcontacting the aqueous solution with a composition comprising a carbonsubstrate having a surface of CO_(x)E_(y), wherein E is selected from atleast one of S, Se, and Te; and wherein x is no more than 0.1, and y is0.005 to 0.3.

Item 12. The method for removing chloramine from aqueous solutions ofitem 11, wherein x is 0.01 to 0.1.

Item 13. The method for removing chloramine from aqueous solutions ofany one of items 11-12, wherein E is sulfur and the sulfur is chemicallycombined with carbon.

Item 14. The method for removing chloramine from aqueous solutions ofany one of items 11-13, wherein the carbon substrate is a microporous,mesoporous, macroporous carbon, or combination thereof.

Item 15. A method of making a carbon oxychalcogenide comprising:contacting a carbon substrate with a chalcogen-containing compound; andheating to a temperature between 300 to 1200° C. in the presence ofoxygen, wherein the form of oxygen is selected from the group consistingof: an inert diluent gas, water, steam, or combinations thereof.

Item 16. The method of item 15, wherein the form of oxygen is selectedfrom the group consisting of dioxygen, sulfur dioxide, water, carbondioxide, or combinations thereof.

Item 17. The method of any one of items 15-16 wherein thecalcogen-containing compound is selected from the group consisting of:elemental sulfur, SO₂, CS₂, H₂S, ethylene sulfide, elemental selenium,SeO₂ and SeS₂, elemental tellurium, TeO₂, (HO)₆Te, and combinationsthereof.

Item 18. A method of making a carbon oxychalcogenide comprising:contacting a carbon substrate with an oxidizing agent to form anoxidized carbon substrate; providing a chalcogen-containing compound;and contacting the oxidized carbon substrate and thechalcogen-containing compound and heating to a temperature between 300to 1200° C.

Item 19. The method of item 18 wherein the oxidizing agent is selectedfrom at least one of: air, ammonium persulfate, aqueous nitric acid,ozone, hydrogen peroxide, potassium permanganate, and Fenton's Reagent.

Item 20. The method of any one of items 18-19 wherein thecalcogen-containing compound is selected from the group consisting of:elemental sulfur, SO₂, CS₂, H₂S, C₂H₄S, elemental selenium, SeO₂ andSeS₂, elemental tellurium, TeO₂, (HO)₆Te, and combinations thereof.

Item 21. A composition comprising a carbon substrate having a surfacecomprising CO_(x)E_(y), wherein C, O, and E chemically interact; whereinE is selected from at least one of S, Se, and Te; and wherein x is 0.01to 0.1, and y is 0.005 to 0.3.

Item 22. The composition of item 21 wherein E is sulfur and the sulfuris chemically combined with carbon.

Item 23. The composition of any one of items 21-22, wherein the carbonsubstrate is a microporous, mesoporous or macroporous carbon.

Item 24. The filtration device of any one of items 1-5, wherein thecarbon substrate comprises less than 0.90, mass % nitrogen based on thetotal mass of the carbon substrate.

Item 25. The filtration device of any one of items 1-5, wherein thecarbon substrate comprises greater than 2.0 mass % sulfur based on thetotal mass of the carbon substrate.

Item 26. The water filtration device of any one of items 6-10, whereinthe carbon substrate comprises less than 0.90, mass % nitrogen based onthe total mass of the carbon substrate.

Item 27. The water filtration device of any one of items 6-10, whereinthe carbon substrate comprises greater than 2.0 mass % sulfur based onthe total mass of the carbon substrate.

Item 28. The method of any one of items 11-20, wherein the carbonsubstrate comprises less than 0.90, mass % nitrogen based on the totalmass of the carbon substrate.

Item 29. The method of any one of items 11-20, wherein the carbonsubstrate comprises greater than 2.0 mass % sulfur based on the totalmass of the carbon substrate.

Item 30. The composition of any one of items 21-23, wherein the carbonsubstrate comprises less than 0.90, mass % nitrogen based on the totalmass of the carbon substrate.

Item 31. The composition of any one of items 21-23, wherein the carbonsubstrate comprises greater than 2.0 mass % sulfur based on the totalmass of the carbon substrate.

EXAMPLES

Advantages and embodiments of this disclosure are further illustrated bythe following examples, but the particular materials and amounts thereofrecited in these examples, as well as other conditions and details,should not be construed to unduly limit this invention. In theseexamples, all percentages, proportions and ratios are by weight unlessotherwise indicated.

All materials are commercially available, for example from Sigma-AldrichChemical Company; Milwaukee, Wis., or known to those skilled in the artunless otherwise stated or apparent.

These abbreviations are used in the following examples: cc=cubiccentimeter, g=gram, hr=hour, in=inch, kg=kilograms, min=minutes,mol=mole; M=molar, cm=centimeter, mg/L=milligrams per liter;mm=millimeter, ml=milliliter, L=liter, N=normal, psi=pressure per squareinch, MPa=megaPascals, and wt=weight.

Methods

Apparent Density Determination

The apparent density of a carbon substrate sample (prepared according toComparative Examples or the Examples according to the disclosure) wasdetermined by tapping a weighed sample in a graduated cylinder untilclosest packing was achieved. The closest packing was deemed to occurwhen tapping did not produce a further decrease in volume of the carbonsubstrate sample.

Preparing Carbon Blocks

40 cm³ of the carbon material (either the carbon-oxychalcogenide sampleor the carbon substrate) was added into a blender. The volume of thecarbon material was determined at the maximum uncompressed density. 40cc of ultra high molecular weight polyethylene (UHMWPE) powder(available under the trade designation “GUR UHMW-PE 2126” from TiconaNorth America, Florence, Ky.) at its maximum uncompressed density wasmeasured and placed into the blender. The carbon material and UHMWPEwere blended for 3 minutes. The mixture was then quantitativelytransferred to a cylindrical shaped mold with a hollow cylindrical corehaving the dimensions of 1.35 in. (34.3 mm) outer diameter, 0.375 in.(9.5 mm) inner diameter, and 3.6 in. (91.4 mm) length. The mold wasfilled using an impulse filling as described in U.S. Pat. No. 8,206,627(Stouffer et al.) to maximum uncompressed density. The mold was coveredand then heated in a convection oven at 180° C. for 50 minutes. Afterheating, the mold was immediately compressed with a piston to a fixedblock length of 3.1 in. (78.7 mm) The mold was cooled to roomtemperature and the resulting carbon block was removed from the mold.Endcaps were applied to the carbon block using a hot melt glue to forman end-blocked carbon sample.

Chloramine Test

The chloramine content of water samples was determined from the totalchlorine content in the samples. Total chlorine (OCl⁻ and chloramines)concentration was measured by the DPD Total Chlorine Method, Hach Method8167, which Hach Company claims to be equivalent to USEPA Method 330.5.The free chlorine (OCl—) concentration was periodically measured by theDPD Free Chloramine Analysis, Hach Method 8021, which Hach companyclaims is equivalent to EPA Method 330.5. Free chlorine was maintainedat a negligible concentration (<0.2 ppm), thus, the total chlorineanalysis was considered a good approximation of the concentration ofchloramines in the water. All reagents and the instruments were thosedescribed in the standard Hach Method and can be obtained from HachCompany, Loveland, Colo.

Chloramine Preparation

3 ppm choramine was prepared by adding the appropriate amount ofcommercial bleach (5.25% NaOCl) to deionized water. While stirring, 1.5equivalents of a solution of ammonium chloride in water was added to thebleach solution and stirred for 1 hour. The pH was adjusted to 7.6 bythe addition of NaOH or HCl and tested using a pH meter (obtained fromThermo Fisher Scientific, Inc., Waltham, Mass., under the tradedesignation “ORION 3-STAR”).

Chloramine Removal Test

An aqueous chloramine test solution was prepared comprising 3 ppm NH₂Cl(prepared as described above) at a pH 7.6 at 27° C. Immediately prior tothe test, the initial total chlorine content of the aqueous chloraminetest solution was measured as described in the Chloramine Test above.With continuous stirring, a 1.5 mL aliquot of a carbon substrate sample(i.e. a sample prepared according to Comparative Examples or theExamples according to the disclosure) was added to the aqueouschloramine test solution. The mass of the aliquot of the carbonsubstrate sample was determined based on the apparent density of thecarbon substrate determined as described above (which was about 0.3g/mL). Immediately after the mixing, a timer was started. After 30 sec,a 25 mL-aliquot of mixture was removed and within 5 sec of removal, themixture was passed through a 1-micrometer syringe filter to removesuspended solids. The chloramine content of the filtered aliquot wasmeasured within 30 sec of taking the 25-mL aliquot as described above.Aliquots from the mixture were taken periodically over the course of 3minutes and analyzed using the Chloramine Test as described above. Theefficiency of the chloramine removal is reported as the % chloraminereduction determined by the equation:

$\left( {1 - \frac{\left\lbrack {{NH}\; 2{Cl}} \right\rbrack{filteredaliquot}}{\left\lbrack {{NH}\; 2{Cl}} \right\rbrack{initial}}} \right) \times 100$

Chloramine Removal Test 2 (Flow-System Method)

Chloramine capacity in a flow-through system was evaluated per a methodbased on the NSF/ANSI Standard 42 (Drinking Water Treatment—AestheticEffects) for chloramine reduction. A 3 mg/L aqueous chloramine testsolution was prepared having a pH of 9.0±0.25; total dissolved solids of200-500 mg/L; a hardness less than 170 mg/L as CaCO3; turbidity of lessthan 1 Nephelometric Turbidity Units; and a temperature of 20±3° C. Thechloramine concentration was controlled at 2.7-3.3 mg/L by the additionof a sodium hypochlorite solution and then addition of an ammoniumchloride solution. The pH was controlled by adding sodium hydroxide asneeded.

An end-blocked carbon sample (prepared as described above) was thenplaced into a standard filtration vessel that allowed radial flow fromthe outside to the inside of the filter media. The vessel was equippedwith an inlet and outlet. The aqueous chloramine test solution was runthrough the filtration system at a flow rate of 0.13 gallons/minute. Inthis test, the water flow rate was held constant to give an acceleratedtest; that is, there was no duty cycle or shutdown period as prescribedin the NSF standard.

The aqueous chloramine test solution described above was flowed throughthe filtration system for 5 minutes to wet out the carbon block sample.After this, samples of the effluent (outflow from the carbon blocksample) were taken periodically and the throughput in gallons wasrecorded. Effluent samples were analyzed for chloramine using theChloramine Test described above. The chloramine effluent concentrationwas then plotted as a function of the aqueous chloramine test solutionthroughput. The maximum effluent chloramine concentration per NSF 42 is0.5 mg/L. Capacity of the carbon block sample is reported as thethroughput attained before the concentration of chloramines in theeffluent rises above 0.5 mg/L.

Carbon Substrate Samples

Carbon Substrate A was an activated carbon powder (nominal −325 mesh,obtained from MeadWestvaco Specialty Chemicals, North Charleston, S.C.,under the trade designation “AQUAGUARD POWDER”) used as received withoutfurther treatment.

Carbon Substrate B (RGC Powder) was an activated carbon powder with anash content of 2.9 wt % (nominal −325 mesh, obtained from MeadWestvacoSpecialty Chemicals, North Charleston, S.C. under the trade designation“RGC POWDER”) used as received without further treatment.

Carbon Substrate C was prepared as follows: Carbon Substrate B (500 g)was added to 2 L of 7.5M HNO₃ in a 5 L kettle fitted with a refluxcondenser and mechanical stirrer. After the evolution of brown NO_(x)ceased, the mixture was refluxed and stirred overnight. Then the mixturewas cooled to room temperature and the solids were collected on asintered glass filter. The solids were washed with ten 1 L-portions ofdeionized water then dried for 16 hr in a 130° C. oven. The yield was532 g.

Carbon Substrate D was prepared as follows: Carbon Substrate B (150 g)was added in portions with mechanical stirring to a solution of 30 g of(NH₄)₂S₂O₈ in 1 L of 2N H₂SO₄. After 20 hr, the solids were collected ona glass filter. The solids were washed with four 1 L-portions ofdeionized water then dried for 16 hr at 130° C. The yield was 158 g.

Carbon Substrate E was prepared as follows: Carbon Substrate B (400 g)was divided into three batches. Each batch was loaded into a ceramicboat and heated at 500° C. in air. The three batches were combined andthoroughly mixed. The yield was 368 g.

Carbon Substrate F was a carbon black powder (obtained from CabotCorporation, Boston, Mass., under trade designation “BLACK PEARL”) usedas received without further treatment.

Carbon Substrate G was an activated carbon powder (obtained from KurarayChemical Company, Woodland Hill, Calif., under trade designation“KURARAY GG”) used as received without further treatment.

Carbon Substrate H was prepared as follows: Carbon Substrate G, 498 g,was added to a stirred solution of 110 g (NH₄)₂S₂O₈ in 1 L of 2N H₂SO₄.After mechanically stirring for 16 hr, the solids were isolated byfiltration, washed with three 2 L portions of deionized water then driedin a 130° C. oven. The yield of oxidized granular carbon was 438 g.

Carbon Substrate I was prepared as follows: Carbon Substrate B, 170 g,and 1 L deionized water were placed in a 3 L reaction kettle equippedwith a mechanical stirrer. A solution of 17 g bromine in 1.4 L deionizedwater was added dropwise with stirring over 1 hr. Stirring was continuedfor 1 hr. Then, the mixture was filtered and the solids washed withthree 1 L portions of deionized water. After drying at 130° C. for 2hrs, the brominated carbon weighed 214 g and was analyzed and found tocontain 3.0% Br.

Carbon Substrate K was prepared as follows: A solution of sodiumhypobromite, NaOBr, was prepared by dropwise addition of 34 g liquidbromine to an ice-cooled, stirred solution of 16 g sodium hydroxide in300 mL deionized water.

A mixture of 170 g Carbon Substrate B, 1 L deionized water and 600 gcracked ice was placed in a 3 L reaction kettle surrounded by an icebath. The above sodium hyprobromite solution was added with stirringover 30 min. Stirring was continued for 1 hr. Then, the solid productwas isolated by filtration, washed with three 1 L portions of distilledwater and dried at 130° C. for 2 hr. The yield was 204 g and wasanalyzed and found to contain 1.4% Br.

Carbon Substrate L was prepared as follows: Carbon Substrate B (400 g)was loaded into a ceramic boat and heated (i.e. calcined) at 400° C. inflowing nitrogen and then cooled in nitrogen atmosphere.

The carbon, oxygen and ash content of carbons can be determined bythermal programmed oxidation. This is essentially combustion in a TGAinstrument. Weight loss is due to loss of carbon as CO₂ and so thepercent oxygen in the sample follows by difference. It transpires thatCarbon Substrate B, C, D, and E contain 0.2, 6.0, 1.9 and 0.4±0.2%oxygen, respectively.

Carbon Substrate M (RGC 325) was a wood-based activated carbon (nominal80×325 mesh, obtained under the trade designation “RGC 325”, fromMeadWestvaco Specialty Chemicals, North Charleston, S.C.) used asreceived without further treatment.

Carbon Substrate N was a wood-based activated carbon (nominal 80×325mesh) obtained from MeadWestvaco Specialty Chemicals, North Charleston,S.C., under the trade designation “AQUAGUARD 325”) used as receivedwithout further treatment. Carbon Substrate N is currently commerciallymarketed for chloramine removal. Carbon Substrate N had a particle sizedistribution, determined by laser scattering, similar to CarbonSubstrate M.

Carbon Substrate O was a coconut shell activated carbon obtained fromKuraray Chemical, Osaka Japan, under the trade designation “PGW100MP”.It had a nominal 80×325 mesh particle size.

General Process for Preparing Carbon Oxychalcogenides:

10 g of a carbon substrate was thoroughly mixed with 1 g finely powderedsulfur (nominally 10 wt %) and transferred to a reactor consisting of a15×1.5 inch (381 mm×38.1 mm) glass tube connected via a 20 mm Solv-Sealjoint (Andrews Glass Co., Vineland, N.J.) to a 10 mm greaseless highvacuum stopcock and vacuum line interface. A plug of glass wool wasinserted ahead of the stopcock to prevent loss of entrained solids.After outgassing for 30 min, the reactor and contents were heated in avertical furnace at 400° C. for 1 hr. After cooling to room temperature,the reactor was again evacuated through a liquid nitrogen-cooled trapfor 15 min, and then opened to isolate the product.

Materials from Examples 2, 3, 5, 6 and 7 were analyzed by TGA (ThermalGravimetric Analysis) to ascertain thermal stability. Each exhibited twoweight loss events with maximum weight losses in the temperature ranges211-22° C. 5 and 307-351° C. (Tmax). Maxima were located by plotting thefirst derivative of weight loss versus temperature.

Tmax for material from Example 5 occurred at 211° C. and 329° C.; and at221° C. and 351° C. for material from Example 7. Each of these twosamples was heated at 170° C. and 315° C. and the volatiles releasedwere examined by mass spectrometry. Only sulfur dioxide was detected.

Examples 1-24 and Comparative Examples A-D

Examples 1-24 were prepared according to the general process forpreparing carbon oxychalcogenides described above. Comparative ExamplesA-D were Carbon Substrates A-D as obtained or prepared as describedabove. Table 1 below summarizes the materials (such as carbon substrateand chalcogen compound, as well as their relative compositions) and theprocess conditions used for preparing samples of each of ComparativeExamples A-D and Examples 1-24. Departures from the general conditionsare noted.

Example 25

Example 25 sample was prepared as follows: Carbon Substrate H, 61 g, and6.3 g finely powdered sulfur were mixed by tumbling and then transferredto a glass tubular reactor. After evacuation for 20 min, the reactor wasplaced in a furnace and heated to 400° C. After 1.5 hr, the reactor wascooled to room temperature and volatiles removed under vacuum. Theresulting product weighed 62.5 g.

Table 1 below summarizes the materials (such as carbon substrate andchalcogen compound, as well as their relative compositions) and theprocess conditions used for preparing samples of each of ComparativeExamples A-D and Examples 1-25. Departures from the general conditionsare noted. Chloramine reduction for the prepared samples for somesamples are also included in Table 1. The chloramine reduction reportedin Table 1 is determined using the process described above after 150seconds.

TABLE 1 Temper- Chloramine Carbon Chalcogen Compound ature ReductionExample Substrate used (%, type) (° C.) (%) Comp. A A NA NA 82 Comp. B BNA NA 41 Comp. C C NA NA 18 Comp. D D NA NA 18 1 B 10%, S 300 39 2 B 1%,S 300 53 3 B 10%, S 400 55 4 C 10%, S 400 50 5 D 10%, S 400 50 6 E 10%,S 400 78 7 B 10%, S  400* 63 8 B 8%, SeO₂ 400 28 9 B 1.5%, SeO₂ 400 3310 B 10%, Se 400 28 11 C 10%, Se 400 51 12 C 13%, Te # 400 42 13 C 10%,SeS₂ 400 28 14 B 26 kPa, SO₂ 400 52 15 B 10%, S and 3%, H₂O 400 22 16 B16%, SOCl₂ 400 52 17 C 11%, (HO)₆Te 400 42 18 C 12%, TeO₂ 400 29 19 B15%, SOCl₂ 400 43 20 C 20%, S 400 57 21 B 12%, CS₂ 400 39 22 C 12%, CS₂400 63 23 F 10%, S  400* 23 24 F 10%, S  400† 10 25 H 10%, S 400 Nottested *performed in air †performed in vacuum # X-ray powder diffractionanalysis of the mostly amorphous product disclosed only weak lines dueto Te and TeO₂, indicating that most of the Te charged was consumed.Mixing of the Te and C, achieved by tumbling for 1.5 hr., is importantin this experiment NA not applicable

Samples of Comparative Example B (Comp. B) and Examples 2-7 above wereanalyzed by X-ray photoelectron spectroscopy (XPS) and the C(1s), O(1s)and S(2p_(3/2)) peaks were integrated to determine the surfacecomposition. The Table 2 below summarizes the XPS data for thesesamples. Note that the values in Table 2 represent the mean ofdeterminations in three separate areas of the samples. While not wishingto be bound by theory, it is believe that these data provide directexperimental evidence for, and quantitation of, oxygen in the resultingmaterials.

TABLE 2 Example Atomic % C Atomic % O Atomic % S Atomic % N Comp. B 96.82.9 0 NA 2 93.2 2.9 3.2 NA 3 92.6 3.4 3.4 NA 4 86.6 8.8 3.0 1.6 5 91.84.2 3.1 NA 6 91.2 5.1 3.1 NA 7 93.8 2.4 3.0 NA NA = below the detectionlimit of >0.1%

Bulk chalcogen content of the samples of some Examples described abovewas determined by combustion analysis. Because some volatile chalcogenby-products can form and because the carbon oxychalcogenides can adsorbsmall, but variable amounts of atmospheric moisture, elementalcomposition cannot be determined by mass balance. Results are shown inTable 3.

TABLE 3 Example Type and % Chalcogen Present 1 S, 9.1 2 S, 0.9 3 S, 8 ±1 4 S, 7.2 5 S, 7.4 6 S, 9.7 7 S, 5.6 8 Se, 3.5 10 Se, 3.9 11 Se, 7.6 12Te, 7.3 13 S, 2.8; Se, 5.4 14 S, 1.9 15 S, 8.9 ± 0.6 16 S, 2.5; Cl, 3.517 Te, 5.8 19 S, 1.6; Cl, 4.5 20 S, 19.0 21 S,1.3 22 S, 5.2 ± 0.9 25 S,5.2 ± 0.9

While not wishing to be bound by theory, it is believed that theresulting carbon oxychalcogenides samples do not include non-volatileby-products that remain to clog small pores. For example, as shown inTable 4 below, the as-received Carbon Substrate B has a BET surface areaof 1637 m²g⁻¹. When Carbon Substrate B is pre-oxidized using the processdescribed above for preparing Carbon Substrate D, its BET surface areais 1632 m²g⁻¹. When the resulting Carbon Substrate D is heated at 400°C. under vacuum with 10 weight percent powdered sulfur (similar to theprocess of Example 5) the resulting carbon oxysulfide sample still has avery high BET surface area (1425 m²g⁻¹). Note that the samples wereoutgassed at 150° C. prior to measuring the BET surface area and N₂ wasthe probe molecule.

TABLE 4 Sample BET Surface Area, m²g⁻¹ Carbon Substrate B 1637 CarbonSubstrate D 1632 Example 5 1425

Example 26

Example 26 sample was prepared as follows: 12 g of Carbon Substrate Iwas mixed with 1.2 g powdered sulfur. The mixture was outgassed at roomtemperature for 2 hr, and then heated under vacuum at 400° C. for 1 hr.After cooling to room temperature, volatiles were removed under vacuum.The product weighed 9.2 g and analyzed and found to contain: S,10.3±0.7%; Br, 1.0±0.09%.

Example 27

Example 27 sample was prepared as follows: 12 g of Carbon Substrate Kwas mixed with 1.2 g powdered sulfur, outgassed for and heated undervacuum at 400° C. for 1 hr. After cooling, volatiles were removed undervacuum. The product weighed 10.2 g and was analyzed and found to containS, 9.7±1.0%; Br, 0.7±0.05%.

Samples of Examples 6, 7, 26 and 27 and Comparative Example B weretested for their % chloramine reduction as a function of time using theChloramine Removal Test described above. The results are shown inFIG. 1. Note that the % chloramines reduction of Examples 6 and 7 werehigher than that of Comparative Example B. Similarly Examples 26 and 27prepared by using different oxidizing agents also had higher %chloramine reduction than that of Comparative Example B. AlthoughExamples 6, 7, 26, and 27 all used the same carbon substrate (RGC) asshown in FIG. 2, the different treatments of the carbon substrateyielded materials with different chloramine removal kinetics. While notwishing to be bound by theory, it is believed that this observation canbe rationalized retrospectively in terms of the oxygen concentrationpresent during the thermal reaction and the amounts and types offunctional groups (e.g. CO₂H, C═O or C—OH) produced during the process.

Example 28

Example 28 sample was prepared by first heating Carbon Substrate B (40.0g) to 180° C. in a crucible, and then adding elemental sulfur (10.0 g,obtained from Alfa Aesar, −325 mesh, 99.5%) with stirring. The sulfurmelted and was incorporated into the Carbon Substrate B.

Four small samples (˜2 g each) of the Carbon Substrate-sulfur mix fromabove were transferred to smaller crucibles with loose-fitting lids tomake up Examples 28A, 28B, 28C, and 28D. Each of Example 28 A-D cruciblewas then individually heated in a nitrogen purged muffle furnace at 180,350, 550 and 750° C., respectively, for 10 minutes. After the heattreatment, each crucible was then transferred to a nitrogen-purgedcontainer for cooling to near room temperature.

Example 28 A-D samples prepared above and Comparative Example A and Bsample were tested for their % chloramine reduction as a function oftime as described above. The results are shown in FIG. 2. The rate of %chloramine reduction of Example 28C, prepared at 550° C., was similar tothat of Comparative Example A, which is a specialty carbon marketed as avery high activity media for chloramine reduction. While not wishing tobe bound by theory, it is believed that as the temperature is increasedduring the step of heating the carbon substrate in the presence ofsulfur, there is a shift in the distribution of acyclic S_(x) (x=2-8)species in the sulfur vapor toward smaller, more reactive oligomers.

The Example 28C sample was analyzed by X-ray photoelectron spectroscopy(XPS) and integration of the C(1s), O(1s) and S(2p_(3/2)) peaks todetermine the surface composition. The surface composition of theExample 28C sample was 90.4 atomic (at) % of C, 2.8 at % of O, and 6.8at % of S. Note that these values represent the mean of determinationsin three separate areas of the sample.

Example 29

Example 29 sample was prepared in the same manner as Example 28C, exceptthat the Carbon Substrate D was used instead of Carbon Substrate B.

Example 30

Example 30 sample was prepared in the same manner as Example 28C, exceptthat the Carbon Substrate E was used instead of Carbon Substrate B.

Example 28C, 29, 30 samples prepared above and Comparative Example Bsample were tested for their % chloramine reduction as a function oftime as described above. The results are shown in FIG. 3.

Example 31

Example 31 sample was prepared in the same manner as Example 28C, exceptthat the Carbon Substrate L was used instead of Carbon Substrate B.

Example 28C, 31 samples prepared above and Comparative Example B samplewere tested for their % chloramine reduction as a function of time asdescribed above. The results are shown in FIG. 4.

Example 32

Examples 32A-32G were prepared using Carbon Substrate B (10.0 g) andgrey selenium (1.0 g, obtained from Alfa Aesar, −200 mesh) following thegeneral process for preparing carbon oxychalcogenides described aboveexcept that the samples were heated to 400° C. for Example 32A, 500° C.for Example 32B, 600° C. for Example 32C, 700° C. for Example 32D, 800°C. for Example 32E, 900° C. for Example 32F and 1000° C. for Example32G. XRD patterns for Examples 32A-32G samples did not include peaks forSe or SeO₂, indicating that all of Se was consumed in the reaction. Bulkchalcogen content of the samples of Examples 32A -32G were determined byusing an ICP optical emission spectrophotometer (Model Perkin ElmerOptima 3300VP obtained from Perkin Elmer, Inc. Waltham, Mass.). Examples32A-32G samples contained 4.2, 5.8, 5.5, 7.1, 7.3, 6.0, 3.6 wt % Se,respectively.

Examples 32A-32G samples prepared above and Comparative Example B samplewere tested for their % chloramine reduction as a function of time asdescribed above. After 300 seconds of testing Comparative Example Bsample removed 51.5% of chloramine After 300 seconds of testing Examples32A-32G samples removed 62.5, 59.4, 54.5, 53.1, 53, 40.6, and 25% ofchloramine, respectively.

Example 33

Examples 33A-33E were prepared using Carbon Substrate B (10.0 g) and CS₂(1.2 g) following the general process for preparing carbonoxychalcogenides described above except that the air was not removedfrom the reactor prior to heating. The samples were heated to 400° C.for Example 33A, 500° C. for Example 33B, 600° C. for Example 33C, 700°C. for Example 33D, 800° C. for Example 33E, 900° C. Bulk chalcogencontent of the samples of Examples 33A -33E were determined by using bycombustion analysis. Examples 33A-33E samples contained 2.4, 3.0, 3.5,3.9, 4.0 wt % S, respectively. Examples 33A-33E samples prepared aboveand Comparative Example B sample were tested for their % chloraminereduction as a function of time as described above. After 300 seconds oftesting Comparative Example B sample removed 53.3% of chloramine After300 seconds of testing Examples 33A-33E samples removed 63.3, 66.7,63.3, 63.3, and 60% of chloramine, respectively.

Example 34

Examples 34A-34E were prepared using Carbon Substrate B (8.0 g) andpowdered SeO₂ (1.0 g) following the general process for preparing carbonoxychalcogenides described above except that the reactor was back filledwith 1 atmosphere of nitrogen after outgassing and the samples wereheated to 500° C. for Example 34A, 600° C. for Example 34B, 700° C. forExample 34C, 800° C. for Example 34D, 900° C. for Example 34E, 900° C.XRD patterns for Examples 34A-34E samples did not include peaks for Seor SeO₂, indicating that all of SeO₂ was consumed in the reaction. Bulkchalcogen content of the samples of Examples 34A -34E were determined byusing an ICP optical emission spectrophotometer (Model Perkin ElmerOptima 3300VP obtained from Perkin Elmer, Inc. Waltham, Mass.). Examples34A-34E samples contained 8.0, 5.1, 5.6, 5.8, 5.3 wt % Se, respectively.Examples 34A-34E samples prepared above and Comparative Example B samplewere tested for their % chloramine reduction as a function of time asdescribed above.

Example 35

Example 35 sample was prepared by first heating Carbon Substrate M (>40cc) to 180° C. in a crucible, and then adding elemental sulfur (0.2 gsulfur per gram carbon, obtained from Alfa Aesar, −325 mesh, 99.5%) withstirring. The sulfur melted and was incorporated into the CarbonSubstrate M.

A sample (˜40 to 100 cc) of the Carbon Substrate-sulfur mix from abovewas transferred to a crucible with a loose-fitting lid. The crucible wasthen placed in a nitrogen purged muffle furnace, equilibrated to 550° C.and held at that temperature for 10 minutes. The crucible was removedfrom the furnace and transferred to a nitrogen-purged container forcooling to near room temperature.

Example 36

Example 36 was prepared and tested in the same manner as Example 35,except that the Carbon Substrate O was used instead of Carbon SubstrateM.

The carbon-oxychalcogenide sample from Examples 35 and 36, as well asCarbon Substrate M and N, were individually made into a carbon blockfollowing the Preparing Carbon Blocks method described above. Each ofthe carbon blocks was tested for chloramine removal following theChloramine Removal Test 2 (Flow-system Method) as described above. Threecarbon blocks comprising the Carbon Substrate N were prepared andanalyzed for Chloramine Removal and 3 carbon blocks comprising theExample 35 carbon oxychalcogen were prepared and analyzed for ChloramineRemoval. The results are shown in FIG. 5, where the carbon block madewith Carbon Substrate M is CS-M, Carbon Substrate N is CS-N, Example 35is Ex 35, and Example 36 is Ex 36. FIG. 5 shows the amount of chloraminepresent in the effluent (in ppm) versus throughput (i.e., how manygallons of the chloramine-containing water were run through the carbonblock).

Shown in Table 5 below is the approximate average chloramine capacitiesfor the carbon blocks tested based on a 0.5 mg/L maximum effluentconcentration.

TABLE 5 Carbon material used to make carbon block Chloramine CapacityCS-M <1 gallon CS-N 30-40 gallons Ex. 35 >400 gallons Ex. 36 >400gallons

Analysis of Hydrogen, Nitrogen and Sulfur

Examples 35 and 36 were analyzed for weight percent Carbon, Hydrogen,Nitrogen and Sulfur by combustion using a LECO TruSpec Micro CHNSelemental analyzer, Laboratory Equipment Co. St. Joseph, Mich. Briefly,the sample is placed in the instrument and purged of atmospheric gases.The sample is then heated to over 1000° C. in the presence of oxygen tocombust the sample. The sample is then passed through a second furnacefor further oxidation, reduction, and particulate removal. Thecombustion gases are then passed through various detectors to determinethe content of the carbon, hydrogen, nitrogen, and sulfur.

A sulfamethazine standard (>99%, from LECO) was diluted to make acalibration curve ranging from 1 mg to 2.6 mg sulfamethazine. Theinstrument is baselined with ambient air until the CHNS detectorsstabilized. Then, 3-4 empty crucibles were measured and set asinstrument blanks. Next, the sulfamethazine standards were analyzed toform a calibration curve. The absolute standard deviation of thesulfamethazine standard (acceptable precision for a pure homogeneousmaterial) for the elements were: <+/−0.3 wt. % for Hydrogen, <+/−0.3 wt.% for Nitrogen and <+/−0.3 wt. % for Sulfur with a limit of detection of0.10 wt % for each of the elements. Examples 35 and 36 were thenanalyzed for their carbon, hydrogen, nitrogen, and sulfur content.Example 35 had 14.42 wt % sulfur and the hydrogen and nitrogen werebelow the limit of detection. Example 36 had 8.44 wt % sulfur, 0.12 wt %nitrogen and the hydrogen was below the limit of detection.

Foreseeable modifications and alterations of this invention will beapparent to those skilled in the art without departing from the scopeand spirit of this invention. This invention should not be restricted tothe embodiments that are set forth in this application for illustrativepurposes.

What is claimed is:
 1. A filtration device comprising a fluid conduitfluidly connecting a fluid inlet to a fluid outlet; and a filter mediumdisposed in the fluid conduit; the filter medium comprising a carbonsubstrate having a surface of CO_(x)E_(y), wherein E is selected from atleast one of S, Se, and Te; and wherein x is no more than 0.1, and y is0.005 to 0.3.
 2. The filtration device of claim 1, wherein x is 0.01 to0.1.
 3. The filtration device of claim 1, wherein E is sulfur and thesulfur is chemically combined with carbon.
 4. The filtration device ofclaim 1, wherein the filter medium comprises the carbon substrate havinga surface of CO_(x)E_(y) and a binder.
 5. The filtration device of claim1, wherein the filter medium comprises the carbon substrate having asurface of CO_(x)E_(y) and a web.
 6. The filtration device of claim 1,wherein the carbon substrate comprises less than 0.90, mass % nitrogenbased on the total mass of the carbon substrate.
 7. The filtrationdevice of claim 1, wherein the carbon substrate comprises greater than2.0 mass % sulfur based on the total mass of the carbon substrate. 8.The filtration device of claim 1, wherein the filtration device is awater filtration device.
 9. A method for removing chloramine fromaqueous solutions comprising: providing an aqueous solution comprisingchloramine and contacting the aqueous solution with a compositioncomprising a carbon substrate having a surface of CO_(x)E_(y), wherein Eis selected from at least one of S, Se, and Te; and wherein x is no morethan 0.1, and y is 0.005 to 0.3.
 10. The method for removing chloraminefrom aqueous solutions of claim 9, wherein x is 0.01 to 0.1.
 11. Amethod of making a chalcogen-containing carbon substrate, the methodcomprising: contacting a porous carbon substrate with a solidchalcogen-containing compound; and heating to a temperature between 300to 1200° C. to form the chalcogen-containing carbon substrate.
 12. Themethod of claim 11 wherein the solid calcogen-containing compound isselected from the group consisting of: elemental sulfur, elementalselenium, SeO₂ and SeS₂, elemental tellurium, TeO₂, (HO)₆Te, andcombinations thereof.
 13. The method of claim 9, wherein E is sulfur andthe sulfur is chemically combined with carbon.
 14. The method of claim9, wherein the porous carbon substrate is a microporous, mesoporous,macroporous carbon, or combination thereof.
 15. The filtration device ofclaim 1, wherein the porous carbon substrate comprises less than 0.90mass % nitrogen based on the total mass of the carbon substrate.
 16. Thefiltration device of claim 1, wherein the porous carbon substratecomprises greater than 2.0 mass % sulfur based on the total mass of thecarbon substrate.
 17. The method of claim 9, wherein the porous carbonsubstrate comprises less than 0.90 mass % nitrogen based on the totalmass of the porous carbon substrate.
 18. The method of claim 9, whereinthe porous carbon substrate comprises greater than 2.0 mass % sulfurbased on the total mass of the porous carbon substrate.
 19. The methodof claim 11 wherein the porous carbon substrate and solidchalogen-containing compound are heated in the presence of oxygen,wherein the form of oxygen is selected from the group consisting of:diatomic oxygen, sulfur dioxide, water, carbon dioxide, or combinationsthereof.
 20. The method of claim 11 wherein the porous carbon substrateand solid chalogen-containing compound are heated in the absence ofoxygen.
 21. The method of claim 11, wherein the solidchalcogen-containing compound comprises sulfur and thechalcogen-containing carbon substrate comprise a sulfur content in therange of 5-15 weight % of the porous carbon substrate on a sulfur-basis.22. The method of claim 11 comprising: mixing the porous carbonsubstrate and the solid chalcogen-containing compound in afirst-container and heating to above a melting point of the solidchalcogen-containing compound to melt the solid calcogen-containingcompound on the porous carbon substrate to form a first mixture; coolingthe first mixture and transferring the first mixture to a reactionvessel that has been purged by an inert gas; and heating the reactionvessel to a contact temperature in the range of 400 to 800° C., therebyvaporizing the solid chalogen-containing compound.
 23. The method ofclaim 11, comprising: mixing the porous carbon substrate and the solidchalcogen-containing compound in a reaction vessel; outgassing thereaction vessel; and heating the reaction vessel to a contacttemperature in the range of 400 to 800° C., thereby vaporizing the solidchalcogen-containing compound.
 24. The method of claim 23, wherein theporous carbon substrate has not been treated by contact with a meltedand cooled solid chalogen-containing compound.
 25. The method of claim11, wherein the porous carbon substrate is a carbon particulate.
 26. Themethod of claim 11, wherein the sulfur comprises elemental sulfur.